1. Field of the Invention
The present invention relates to a process for the hydrodesulfurization of a hydrocarbonaceous oil at conditions to effect conversion of the heavy constituents of the oil to lower boiling hydrocarbons utilizing a catalyst containing a Group IIA metal component such as magnesium.
2. Description of the Prior Art
U.S. Pat. No. 4,098,683 discloses a hydrodesulfurization process utilizing Co-Mo or Ni-Mo on alumina and treating a residual oil at 600.degree. to 800.degree. F. Alkaline earth metals such as magnesium can be added in an amount of 1 to 5 percent to the catalyst.
U.S. Pat. No. 4,061,563 discloses a nickel-tungsten on silica-alumina catalyst for hydroprocessing hydrocarbons. A nickel-molybdenum catalyst is disclosed as conventional for hydrocracking accompanied by hydrodesulfurization. The addition of an alkaline earth metal to a hydroprocessing catalyst is also disclosed.
U.S. Pat. No. 4,203,829 discloses a hydrodesulfurization catalyst comprising cobalt, molybdenum, alumina and magnesia. The compositions of the catalyst are shown in Table I, column 5. Magnesium oxide comprises a major portion of the catalyst.
U.S. Pat. No. 4,140,626 and U.S. Pat. No. 4,132,632 disclose desulfurization catalysts comprising cobalt, molybdenum and a magnesium oxide-alumina support comprising more than 70 percent magnesium oxide.
A problem that is encountered when heavy oils having constituents boiling above 1020.degree. F. are hydrode-sulfurized at severe conditions (e.g., higher temperatures where cracking of some of the 1020.degree. F.+ materials occurs) is formation of insoluble precipitates that cause plugging of the reactor or of the downstream equipment, that is, deposition of sediment. Plugged reactors usually means premature closing of the reactors for catalyst replacement.
It has now been found that sulfur-containing heavy oils can be desulfurized while simultaneously converting at least a portion of the 1020.degree. F.+ materials and minimizing the formation of insoluble precipitates in process by utilizing a catalyst having a specified amount of a group IIA metal component.